Add oil to large saucepan and heat. Add onion and cook until soft. Add ground beef, increase heat and cook for 5 minutes, stirring from time to time, until the meat is no longer pink. Stir in beans, tomatoes, stock, Mrs. Dash® Extra Spicy Seasoning Blend and chocolate. Bring to a boil, cover and simmer gently for 1 hour. Ladle into mugs or large cups and garnish as desired.